Rails of the type mentioned above are known from many examples.
CH 515 819 describes such a rail in which the C-shaped sides of the rails engage the side wheels of the trolley. The wheels in turn run on the upper or lower edges of the C-shaped sides. For lateral support, radially projecting support rims, which function in concert with the side parts of the sides of the rail, are provided along the circumferential running surfaces of the trolley wheels on the side facing away from the sides. Because they can be easily damaged, the support rims make the trolley wheels relatively complicated and vulnerable. The support rims may also cause damage to a surface on which the trolley is placed outside the rail. Finally, the rail is also relatively complicated, because it requires a ledge on which the support rims can be supported laterally to be present between the sides and the base part of the rail. In overhead suspension operation, the support rim exerts force on the outer edge of the sides, making it necessary for these parts to be of thick construction to prevent bending. They therefore require a relatively high amount of material and are thus costly.
WO95/14599 presents an improved rail in which the C-shaped sides connect evenly to the base part and no ledges are necessary. For the trolley wheels, the support rims are replaced by lateral guide wheels within the wheels, which abut the center of the sides. Because the guide wheels engage the center of the sides, less supporting force needs to be exerted by the sides and the rails can therefore be of lighter construction as a result of the supporting forces acting at a lower level. However, this rail may only be used by trolleys with lateral guide rollers.